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1977, 1978, 1979 Cadillac Differences?

Started by Coupe Deville, October 13, 2015, 01:07:41 PM

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Coupe Deville

Hello everyone.

I am hoping to pick up a new daily driver soon. I find the 77-79 RWD Coupes very good looking. I know these cars are very reliable with the 425 and the TH400? I have always wondered this and I was wondering if someone could simplify this for me. What are the cosmetic differences in the 77-79 Coupe Devilles? I have been looking at pictures online and the front ends all seem the same to me. Was one of these years better than the other? Are there any things to look out for besides the usual when buying A 70's Cadillac. Another thing is, living in California I will have to smog the car. I know how these primitive emissions systems work and how to keep them up, but getting it to pass smog is something Ive never had to deal with before. I would just like to get some input.

Thank you for your assistance.

-Gavin   
-Gavin Myers CLC Member #27431
"The 59' Cadillac says more about America than a whole trunk full of history books, It was the American Dream"

James Landi

HI Gavin,

During the early 1990's, I owned, in succession, four of these-- all under 100K miles, and they ran well, were quiet, and very comfortable and relatively nimble to drive in traffic.  At the end of the run, in 1978, an ERG valve system appeared and I believe some other anti-pollution devices were added... I can't recall if and when the catalytic converters were added.  My cars did not leak or burn oil, and were durable.  I sold my last one when I fell in love with the mid-80's Eldos-- (Still own one).   I always felt so disappointed that the rock-solid drive train could not be converted in to new(er) models... much of the engineering "DNA" disappeared by 1981.

Barry M Wheeler #2189

The main differences are in the grille. 1977 had a horizontal look in the squares, 1978 was perfectly square but bigger, and 1979 had smaller squares. Tail lamps, 1977 had a 1970 appearance, and 1978/79 were the same except for the red plastic. 1977/78 had a large horizontal bar for spokes on the steering wheel and 1979 used the same wheel that was used until whenever they added an air bag. I think the Fleetwoods in 1977/78 had footrests in back, the '79 did not.

I prefer the 1979s. My wife owns a '79 Fleetwood with 160K on it and it's the quietest car we own. And probably the best.
Barry M. Wheeler #2189


1981 Cadillac Seville
1991 Cadillac Seville

Eric DeVirgilis CLC# 8621

#3
Grille:

1977 Horizontal Egg Crate. Cadillac script (in black) embossed in chrome bar above grille

1978 Egg Crate with emphasis on vertical sections of 3 large squares. Chrome Cadillac script nameplate in painted area on header panel.

1979 Fine cellular texture of 150 small squares. Taller chrome bar above grille with Cadillac script returned to the bar.

Front turn signal lenses: 1977: Clear; 1978 & 1979 Amber.

Rear Bumper/Taillamps:

1977: Top half of taillamp/brake lamp/turn signal with exposed lens which also serves as side marker light; rectangular reflectors nestled between rear bumper rub strips of either side.

1978 & 1979: Taillamp lens fully encapsulated by chrome bumper end. Side marker light built into the side of vertical bumper end. Rear reflectors no longer between rub strips in rear bumper. They are now in the bottom of the taillamp in the bumper end.

1979: Taillamp lens has chrome "bishop's hat crest" inserts. 1978 & 1977 it was only relief molded into the lens and edged in chrome paint.   

Hood Ornament: (DeVille Only)

1977: "See-thru" skeletal Crest

1978 & 1979: Coat of Arms w/ Color insert. 

Vinyl roof material: "Tuxedo Grain" (crosshatch pattern) 1977;

Very Late 1977, 1978 & 1979 "Elk Grain"
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

Eric DeVirgilis CLC# 8621

#4
Mechanically, Tri-7 are identical however 1979 is the softest riding and quietest of the three.

1979 is the only year only for simulated burled walnut wood applique. It was also especially prone to fading in the sun which is perhaps why it was only used in one year. 1977/1978 used simulated rosewood interior wood trim.

1979 was the first year digital ETR radio with LED digital display w/ clock was standard.

1979 was also first for seat belt chimes (all models) instead of buzzer - another nice touch. (Chimes first appeared on 1976 Seville).

Personally I like the 1977 the best because of its distinctive taillights which beautifully outline the rear of the car at night in profile. From the rear, 1977 looks trimmer than the other two years.

Best to concentrate of finding one in the model, colors and condition you want before model year. 


A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

JerRita

I agree with Eric the 77 is my favorite style also
Jerry and Rita Trapani #15725 Caddymaniacs

g27g28

I vote 79.  Better seat pattern and steering wheel.   I always liked the Y shaped window switches on the earlier ones though.  Find a Deville d'Elegance if you can :).  It's like sitting in your favorite recliner. 
1941 Series 62
1954 Coupe DeVille
1978 Phaeton
1980 Fleetwood

TJ Hopland

I too think mechanically they are pretty close.   

EGR came in 73.  Cat converter 75.   In the 77-79 range some had smog pumps some not.  I have seen several 78's that didn't have em.  The 79's and 77's I have seen had em.  I suppose maybe it depended on where they were sold originally. 

77 I believe still had the vacuum powered air ride (if equipped).  78 had the electric pump under the hood.
 
77 I believe still had the mostly mechanical cruise control (if equipped) with the gearbox in the speedometer cable.  78 had an electronic sensor in the speedometer head then an electronic module that operated solenoids on the mechanical stuff. 

79 I think was the change to the more plastic trunk pulldown that was used through the 80's. 

78 I think was the change to the plastic blade fuses (except eldorado that changed next year).  Every 78 I have tangled with had melted relay socket for the heater blower so must have been part of the fuse change that caused that.  Not too hard to repair but some folks did some pretty nasty work around hacks that can be messy. 

I have run into several cars from that era where the charcoal canister had deteriorated internally and was sending little bits of charcoal into the carb and causing trouble.   Quick fix for that was to insert an inline fuel filter in the line to trap the bits. 

The straight bar 77-78 steering wheel was prone to some sort of shrinking or cracking issues that besides looking bad caused issues with the horn.   When I got my 78 horn didn't work.   While working on other stuff I found the wire cut under the dash and 3 places under the hood which still didn't fix it so must have been cut somewhere else too.  Over the winter had a problem with the battery going dead.  Turned out to be the horn relay.  Something in the wheel must have shrunk or expanded in the cold and shorted which then engaged the relay.   Would have also done the horn too if the wires had not been cut.  At least I learned why someone cut the wires.    I never did really dig in and find the issue. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

jwjohnson86

Noted this 1977 in Ohio claiming to have 13000 miles.  Lots of photos which you usually don't see on Craigslist ads.  Happy hunting!

Jason Johnson

http://detroit.craigslist.org/mcb/cto/5253330002.html
1970 DeVille Convertible 472 cid

http://bit.ly/1NhHpdt

Barry M Wheeler #2189

It sounds as if it's in Alan Haas' neck of the woods. He might be available to take a look at it. What a neat color.
Barry M. Wheeler #2189


1981 Cadillac Seville
1991 Cadillac Seville

Eric DeVirgilis CLC# 8621

New fuse style began on all downsized GM full size cars in 1977. Eldorado and Seville retained the old glass tube fuses until the final year of their respective styling generations of 1978 and 1979.

Cars destined for California received the extra pollution equipment regardless of model year.

New Southgate CA plant began producing DeVilles in the 1979 model year. Pollution equipment was installed in all Southgate built cars.

Steering wheel horn pad of 1977 & 1978 was notorious for contracting in extreme cold triggering horns in the middle of the night. A lot of 77/78 had burned out horns as a result. Curiously, the identical style steering wheel was used on the 1979 Buick Riviera.

Redesigned 1979 Cadillac steering wheel did not have this problem.

Power trunk mechanism was identical for all 1977 - 1979 Cadillac C body cars.

New integral trunk motor/ switch assembly began 1980 and was used well into the '90s.   
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

66 Eldo

Quote from: Eric DeVirgilis CLC# 8621 on October 13, 2015, 04:11:36 PM
Mechanically, Tri-7 are identical however 1979 is the softest riding and quietest of the three.
[/b]

Interesting Eric, were there differences with the spring rates or shock absorber valving for the 79s to achieve this? Wonder if the part numbers for springs and shocks are different?

I would take any '77-'79 Deville But to each his own. So FWIW, my preferences and observations are:

> Prefer the taillights of the '77 as they remind me of the '69 and have more detail than the 78-79.
> Prefer the leather seat pattern on the 77-78 and my observation has been the leather interiors in the 79 (including Seville) never seem to hold up as well here in Southern CA. Did the flat inserts have anything to do with this?
> Really prefer the squares in the 78 grille. Coupled with the amber turn signal lenses its my favorite look.
> Prefer the rosewood interior panels in the 77-78 over the burl pattern in the 79. Its all fake but the 79 looks really fake and as mentioned fades.
> No preference on steering wheels although the 79 does not have the top trim to crack.

77 or 78 for me with the 78 having a slight edge due to the grille.

My parents had a 78 CDV for years an I did the maintenance on it. Always passed smog here in CA with an occasional EGR valve replacement due to bad diaphragms in the aftermarket replacements. The smog limits are pretty high for these years and not having a computer controlled carburetor really helps in the event it does not pass. So long as the engine compression is good, egr valve working, timing and carb adjusted, it will pass.

Eric DeVirgilis CLC# 8621

Interesting the opinions of the different styling elements of the Tri-7 cars.

Nothing wrong with the '78 grille but I always felt the '77 grill with the traditional egg crate texture said Cadillac a little better. Also preferred the clear turn signal lenses as well...no matter - it's all good.  :)

Suspension had always the subject of continuous improvement at Cadillac and extra sound deadening materials were used in '78 and '79 above and beyond that used in the '77.



A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

Walter Youshock

Paint on the trunk was poor in '77 and '78 devilles.  Both my '77 and my uncle's '78 linden cars had paint that fell off the trunks.
CLC #11959 (Life)
1957 Coupe deVille
1991 Brougham

Coupe Deville

Hello everyone!

Thank you all for adding something. This is just the kind of input I was looking for. I still have to finish up my project 72' and get it sold, so it will probably be a month before I start looking at cars. I really like that these years have interiors that are like living room couches, and the weight Is roughly 800 pounds lighter than my CDV. And the prices for these 3 diffrent years are very attractive. I always see good deals for these in my area. I'm thinking one of these years will become my new daily driver. I want to get my other low mileage 72' back in the garrage. Good to know that smog isn't a big problem. I know that can become a real headace.

Thanks!

-Gavin 
-Gavin Myers CLC Member #27431
"The 59' Cadillac says more about America than a whole trunk full of history books, It was the American Dream"

Barry M Wheeler #2189

Got to get the shop manual out. Drove the '79 to Maaco this AM and about froze to death. Door must be stuck between heater and A/C.
Barry M. Wheeler #2189


1981 Cadillac Seville
1991 Cadillac Seville

Eric DeVirgilis CLC# 8621

I would agree the Detroit cars tend to have been built and finished with more care than the Linden cars on average.

A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

C.R. Patton II



Which year had the best functioning sunroof?
All good men own a Cadillac but great gentlemen drive a LaSalle. That is the consequence of success.

Barry M Wheeler #2189

Chuck, as all three years had the identical installation (as far as I know), any answer would be subject to the care of the installer, which day of the week the car was produced (according to popular superstition), and the care the car was given in use. We can't flip a coin three ways, so your guess is as good as anyone. The option is rare in any case. I have not used the sunroof in my 1981 Seville except a couple of times to make certain that it works for judging. The operation is relatively violent, and after opening, somewhat noisy. So, I'm leaving it alone.
Barry M. Wheeler #2189


1981 Cadillac Seville
1991 Cadillac Seville

66 Eldo

Quote from: C.R. Patton II on October 15, 2015, 01:28:58 PM

Which year had the best functioning sunroof?

Quite a few Cadillacs during these years had aftermarket American Sunroof Corporation (ASC) sunroofs installations sublet by the selling dealer. The ones I had worked well.